In a rigorously authentic ḥadīth the Prophet (peace and blessings be upon him) said:

“Every newborn comes forth upon the fitrah; it is his parents who turn him into a Jew, a Christian, or a Magian—just as an animal gives birth to a sound offspring; do you ever find it born mutilated?” Both al-Bukhārī and Muslim relate this narration.

In another report in Ṣaḥīḥ Muslim the Prophet (peace and blessings be upon him) said:

“Allah, Blessed and Exalted, declares: ‘I created My servants upright (ḥunafāʾ), but the devils diverted them; they made unlawful for them what I had made lawful, and they commanded them to associate with Me that for which I sent down no authority.’”

The Exalted One also says:

“So set your face steadfastly toward the religion as a ḥanīf—the natural disposition (fitrah) upon which Allah has created mankind; there is no altering Allah’s creation. That is the upright religion.” (Sūrat al-Rūm 30)

This is the creed of Abraham, whom Allah took as an intimate friend.

He further says:

“Who could have a better religion than one who submits his whole being to Allah while doing good, and follows the creed of Abraham, a ḥanīf—and Allah took Abraham as an intimate friend.” (Sūrat al-Nisāʾ 125)

His words “submits his whole being” mean that he purifies his intention and his deeds for Allah alone while excelling in those deeds, so that Allah alone is the One he worships through righteous action. Hence ʿUmar ibn al-Khaṭṭāb (may Allah be pleased with him) used to say: “O Allah, make all my deeds righteous, and make it—”